Clinker removal unit for small, stokerfired, coal-burning heaters



Dec. 13, 1966 J. L. MARGETTS 3,291,080

BURNING HEATERS CLINKER REMOVAL UNIT FOR SMALL, STOKER-FIRED, COAL- Filed July 6, 1965 F/G. Z.

INVENTOR. JOHN L. MARGETTS %(MW ATTORNEYS United States Patent 3,291,080 CLINKER REMOVAL UNIT FOR SMALL, STOKER- FIRED, COAL-BURNING HEATERS John L. Margetts, 2182 Berkley Ave., Salt Lake City, Utah Filed July 6, 1965, Ser. No. 469,620 4 Claims. (Cl. 11045) This invention relates to small, Stoker-fired, coal-burning heaters of the type disclosed more fully in my copending application for patent Serial No. 469,813 filed July 6, 1965 and is particularly concerned with the disposal of clinkers created during the operation of such heaters.

Heaters of the type concerned are stoked by a feed assembly that pushes coal upwardly into a firebowl. As the coal is burned a residue of ash is formed. Some of this ash then melts together to form hard clinkers. As additional coal is moved into the bowl the previously formed residue is pushed out of the firebowl. Since the ash and clinkers form an insulation, tending to confine the fire and increasing its burning efficiency, and since they may still be hot, they are desirably kept in close proximity to the firebowl and heat exchanger for a period of time. Periodically, however, the accumulated residue must be removed from the heater so that additional coal can be fed thereinto.

Because clinkers formed in the operation of the large size stoker fired heaters and furnaces used heretofore have been extremely hard, often as hard as glass, it has not been practical to break them and to remove them with the softer ash. Such clinkers have commonly been removed through an access door to the firebowl with the use of tongs. The ash has been left to eventually melt into a clinker that is subsequently removed.

With small heaters, such as are disclosed in my aforementioned copending patent application, however, the slow burning rate of the coal, i.e., three to six pounds of coal per hour, while creating the usual residue ash creates fewer than usual clinkers, with those created being much more friable and more easily broken than those large and solid clinkers created in more rapid burning heaters and furnaces.

It is an object of the present invention to provide a means for periodically breaking the friable clinkers developed in small heaters into pieces small enough to fall with the ash to the bottom of the heater, from where they are easily removed through an access door.

A principal feature of the invention is the use of an ash ring that is rotated to force upstanding breaker pins through the clinkers as they rest on a sloped retainer plate. As they are broken, the pieces of clinker are directed by the plate downwardly to a residue receiving compartment at the bottom of the heater housing. An actuator rod having a gripping means conveniently positioned outside of the heater housing is provided for oscillating the ash ring.

There is shown in the accompanying drawings a specific embodiment of the invention representing What is presently regarded as the best mode of carrying out the generic concepts in actual practice. From the detailed description of this presently preferred form of the invention, other more specific objects and features will become apparent.

In the drawing:

FIG. 1 is a partial side elevation view of a heater embodying the invention, with portions broken away to show the ash ring and breaker pins, the actuator rod, and the residue receiving compartment;

FIG. 2, a horizontal section taken on the line 22 of FIG. 1; and

FIG. 3, a similar view taken on the line 3-3 of FIG. 1.

Referring now to the drawing:

3,291,689 Patented Dec. 13, 1966 In the illustrated preferred embodiment a small stokerfired heater, shown fragmentarily at 10, has a housing 11, a firebowl 12 inside the housing, and a heat exchanger 13 surrounding and extending above the firebowl.

Coal is fed to the firebowl through a delivery tube 14 and air is directed to the firebowl through an overfire feed tube 15 and a duct 16 that supplies air through a plenum chamber 16-1 to tuyeres 17 forming a portion of the firebowl. The operation of the coal feed unit inside delivery tube 14 and the manner in which air is supplied the burner are all as fully in my aforementioned copending application.

As coal is moved into the firebowl, ash and clinkers formed by previously burned coal are pushed out. The ash forced out tends to fall over the lip of the firebowl formed by the tuyeres 17 onto an ash ring 18 that surrounds the tuyeres. As illustrated, ring 18 rests on protrusions 17a formed integrally with the tuyeres. Some of the accumulated ash tends to fall from ring 18 to the residue compartment 19 of housing 11, but the remainder will be held on the ash ring or on a plate 20 that engages the interior wall of heat exchanger 13 and slopes downwardly therefrom to a level below and spaced from the upper edge of the firebowl, but above the top surface of the ash ring. The clinkers that are formed, being too large to fall through the opening between the ash ring 18 and plate 20, will also be held on the plate. Thus the clinkers, and accumulated ash are retained in close proximity to the firebowl to provide desired insulation and confinement until the clinkers are broken and the ash is shaken from the ash ring in a manner to be described.

The clinkers are broken into small pieces and allowed to fall to ring 18 and then to the bottom of housing 11 by movement of pins 21 that extend upwardly from ring 18.

To move pins 21, it is only necessary for a user to reciprocate a handle 22 that is pivotally connected at 23 to ring 18 and that extends through the housing 11. As the handle is reciprocated, ring 18 is oscillated, and the pins engage the large clinkers, reducing them to pieces small enough to pass through the opening between the ash ring and plate 20. As the ash ring is rotated and pins 21 engage the clinkers the ring is vibrated so that ash and pieces of clinker accumulated on it fall to the residue receiving compartment 19.

It is important that pins 21 be as long as possible, while still being protected from the direct blast of heat radiated outwardly from the firebowl. Thus, they cannot extend so far above the upper edge of the firebowl that they are not shielded by the tuyeres. If they are subjected to direct heat from the firebowl they may melt down, or bend, such that they cannot reach clinkers resting on the plate 20. The pins must be as long as possible to effectively engage the clinkers, and to thoroughly break them.

Periodically, or whenever desired, the accumulated ash and pieces of clinker are removed from compartment 19 through access door 24 in housing 11.

Whereas there is here illustrated and specifically described a certain preferred construction of apparatus which is presently regarded as the best mode of carrying out the invention, it should be understood that various changes may be made and other constructions adopted without departing from the inventive subject matter particularly pointed out and claimed herebelow.

I claim:

1. In a small, stoker-fired coal-burning heater, a housing; a firebowl mounted above the bottom of said housing; means for feeding coal upwardly through said firebowl; a heat exchanger surrounding said firebowl within said housing; a plate surrounding the firebowl and sloping downwardly from engagement with the heat exchanger to below the upper edge of the firebowl in annularly spaced relationship therewith; an ash ring spaced below the plate and surrounding the firebowl below the space between the plate and the firebowl; a circumferential series of mutually spaced pins fixed to said ring and extending upwardly therefrom between the firebowl and the plate and terminating in the vicinity of the upper edge of the firebowl and the lower end of the plate; means for rotating said ring around the firebowl; and an access door through said housing below the level of the firebowl.

2. The heater of claim 1, wherein the firebowl includes tuyeres forming an upper peripheral edge thereof and wherein the pins fixed to the ash ring extend upwardly therefrom to a level just below the direct path of heat radiated outwardly from the firebowl over the upper edge of the tuyeres.

3. The heater of claim 2, wherein the means for rotating the ash ring around the firebowl comprises an elongate rod pivotally connected to the outside periphery of the ring and extending through the housing.

4. The heater of claim 3, wherein the tuyeres include protrusions extending outwardly therefrom and wherein the ash ring rests freely on said protrusions.

References Cited by the Examiner UNITED STATES PATENTS 1,598,579 8/1926 Van Brunt et al 11045 1,982,372 11/1934 Christianson 11045 2,306,189 12/1942 Schweickart et al. 11045 KENNETH W. SPRAGUE, Primary Examiner. 

1. IN A SMALL, STOKER-FIRED COAL-BURNING HEATER, A HOUSING; A FIREBOWL MOUNTED ABOVE THE BOTTOM OF SAID HOUSING; MEANS FOR FEEDING COAL UPWARDLY THROUGH SAID FIREBOWL; A HEAT EXCHANGER SURROUNDING SAID FIREBOWL WITHIN SAID HOUSING; A PLATE SURROUDNING THE FIREBOWL AND SLOPING DOWNWARDLY FROM ENGAGEMENT WITH THE HEAT EXCHANGER TO BELOW THE UPPER EDGE OF THE FIREBOWL IN ANNULARY SPACED RELATIONSHIP THEREWITH; AS ASH RING SPACED BELOW THE PLATE AND SURROUNDING THE FIREBOWL BELOW THE SPACE BETWEEN THE PLATE AND THE FIREBOWL; A CIRCUMFERENTIAL SERIES OF MUTUALLY SPACED PINS FIXED TO SAID RING AND EXTENDING UPWARDLY THEREFROM BETWEEN THE FIREBOWL AND THE PLATE AND TERMINATING IN THE VICINITY OF THE UPPER EDGE OF THE FIREBOWL AND THE LOWER END OF THE PLATE; MEANS FOR ROTATING SAID RING AROUND THE FIREBOWL; AND AN ACCESS DOOR THROUGH SAID HOUSING BELOW THE LEVEL OF THE FIREBOWL. 